Combustion chamber



July 25 1933 A. u. wETHRBr-:E 1,919,285

' coMBUsTloN CHAMBER Filed Nov. 19. 1951 2 Sheets-Sheet 1` W W y HMM/lego( July 25, 1933. A. u. WETHERBEE COMBUSTION CHAMBER Filed Nov. 19, 1931 2 Sheets-Sheet 2 lof invention just mentioned vot tlie'followmf'. l y l An object is to provide a newfandimproved Patented July 25, 1933 ir- UNIrEo--STATESrArENr orrici:

ASHUAR' n. WETHEBE, or' nvANs'roN,rLLIN'o'rs,Y AssreNoR .'ro-An'rQGAs CORPORA- f' rrI'o'N, or' CHICAGO, 1-rL1NOIs,.A GORPoltA'rION ORDELAWARE 'coMBU-'s'rron CHAMBER pending application Serial )10.493537 tiled'.

November 5, 1930. Y v

i The principal objects of the presentinvention are the same as thosevof my p-revlous with the'v addition `combustion chamber comprising `i'serleso elements constituting j interloeking refractory 7 a combustion 'chamber'adapted-for installation `in heating systems 'orijginallydesigned y for the burningr off solid vor l'iouidfuels.

' Another object of'tlie'inveiition-1is to pro-1 vide a .combustion@chamber or conversion burner t or installation in 'heating V'systemsor 'furnaces and inw'vhich none'o'fthe refractory elements of` said chamber Contact with the interior Walls of the firepots'of said systems.

A further object is to provide a. combi-ISL, tion chamber composed ofj a plurality `'of 1n-` terloeking refractory I(dements designed to permit 'expansion and' contraction"thereof without diitl'u'bingthe inter-relationsllnp between said elements; l 4

A .still further Objectis to -provide a new and improved form of radiant elements.

An additionalobjectis toprovide' Va combustion chamber having a base ring constructionally arranged for the super-position of a plurality of' refractory elements thereon Wh ielrinterloektherewith and between which a series of narrow slots are provided for the exit of the. gases oteombustion.

An additiol'ialobject of the invention is to provide a. refractory combustion .chamber composed of av series of elements of refractory material defining a combustion chamber anda top covertherefor which projects-bef l yond the exterior surfaces of said combustion' chamber.

Another important objectief the invention' is to simplify the. construction of-a refractory `combustion chamber by building it up' of sepa-rate elements. ot. ceramic material or the like, preferably-in the generalmanner of a log cabin whereby the. end of each' element 'serves to separate tirol adjaeent'elenients and' form an elongated aperture tlwrebetween. Whether or not arranged 1n.]ust,th 1 s' manparticular-1 ly to a gas burner suitable forfusein heatnw' uelsand constitutes an iinprove' I separate elements be arranged 1n vertical hroivs, 'each' row forming oneside of the comf-bustion chamber,

vvbetween adjacent elements ineach row.

'Additional objects and advantages willbe and V preferably with spaces apparent from the following,description of -jan embodiment ot the invention.

In general v the present. invention operates on the same principles as the one forming the 4subject of the aforementioned application,

perimposed interlocking sectors forming a base for a plurality of superimposed refrac-v tory elements arranged .in y interlocking relationship, preferabl'y'bml't up like a log cabin or otherwise arranged in vertical rows as described above, and which permit of expansion and contraction'of said elements Without dis- 1 tortion lor rupture ofthe same. The tops of the' sectors vare lpreferably formed with depressedportions 'extending `part way along the surface thereof. and intowhich the first -rowof refractory elements are adapted to fit and .interlock with said. portions. When Athe .refractory segments have `been laid. up inV position they forma stack of 'approximately cylindrical proportions containing the maximum amount of surfacefor securing surface catalysis and the interstices or slots between the respective elements are'proportione'd to permit the products of combustion to escape from the inside to the outside of the cylinder such that a maximum amount of radiant v,energyiis emittedrom the refractory el ements'.

In thedr'anings'fivhich represent-an exemplary embodiment voi the 'invention and wherein like' reterence'A characters `designate ....Fig. -1 is an isometric view, partly in section; illustratingr the preferred construction of the combustion' chamber ofthe invention. Eig. 2 isa view of tbevbase sectors in assembledposition with a' plurality of radiant elements and the top yor cover disposed 'thereabove.illustrating,r one method of assembling theparts. Y

f Fig. '3 is a ,-planviev ot a roivfof the refractory elements in assembled position.

consider it verydesirable that these` Fig. 4 is a top, Fig. 5 affront and Fig. 6 a bottom view of one of the refractory elements.

Fig. 7 is a sectional View thru two of the radiant elements as if taken on the-line 7-7 of Fig. 4, illustrating the relative positions of the radiant elements when in assembled position. Y

Figure 8 is a perspective view of a modied arrangement and form of refractory members. v

In the exemplary embodiment of the invention the casing 10 is of such ,size and configuration as to be projected thru the ash it door ofa .furnace or heating system an is provided with an opening l1 therein over which. the combustion or burner chamber is assembled. The casing at its exterior end is provided withsuitable connections and controls asrequired for the eiicient operaf tion of the system.- Enclosed within the casing is a mixing tube 12 thru whichv the primary combustible mixture is -suppliedto the burner element 13 which has a deilector cap 14 for directing the mixture and secondary air outwardlyinto proximity to the walls of the combustion chamber.

These devices as substantially described vare shown in m copending application heretofore -referre vto and their operation is therein fully set forth. -I- do not. therefore, intend to claim them herein are vclaimed in that application, and for a more full explanation of their operationthan is obvious from the description herein given,

reference is made to said application.

s The base section of the combustion chamberxnay beand ispreferablymade up of a series of separable elements to facilitate manufacture and assembly of the construction and generally comprises a ring 15substantially triangularv inl cross section, with the interior face or side thereof hollowed out in a somewhat bowl-shaped manner as illustrated. Superimposedgon this bowl-shaped ring are three sectors 16 interlocking with each other and with the basering to form an essentially tight chamber. The interlocking Vrelationship may be accomplished'in various ways and may be in the form of a-lapped joint 17 between the sectors and between the sectors and the ring 15.

- With, the interlocking feature between the sectors and between substantially tight cylinder is :formed for retainingthe gases during they preliminary stages of their combustion and the construction is such as to allow for a free expansion and. contraction of the elements when subjected to the gases. The ring and the sectors may be re tained in position bv any suitable means, such as a band 18, which, while retaining the elements in position, permits expansion and contractlon thereof.

insofar asl they of the combustion chamber.

the sectors and ring a] intense heat ofl the burning y*The upper portions 19 of the sectors are extended, as well as depressed, to form a recess in which the first segments, to be later described, are adapted to repose. The end walls of the recesses are coterminus 'with the tops of the sectors and are notched at 21 for cooperation with the end portions of segments to support the segments in spaced relation to said portion so as to leave a small narrow orilice or slot therebetween corresponding to the `slot between successive superimposed segments. The special arrangement of the/depressions and extensions is such that Athey support the first three segments in such' position that the additionof `three more segments will form a hexagon.' ,Although it is to be understood that while thesectors are formed tion is not limited to this construction but may be varied for a greater or lesser number of segments. The ring, sectors, and segments are preferably` composedof kceramic or refractory material capable of AwithstandinfY theintense heat to which-they 'are subjecte said materialsbeingl well known in the art.

The segmentsQQ. may takeany desired-form but'preferably comprise an elongated body portion 23 provided with `a shoulder or flange 24 adjacent the ends thereof.A The bottom portion '25 'of which'extends slightly below thebottom face ofthe body. Protruding fromeach shoulder and generally axially to the direction of the body portionis'y a web or neckj26 which terminates in a head 27 at its distal end. In elevation this web or neck is preferably slightly greater 'than half the thickness ofthe body portion of the segments and is slightly'inclinedoutwardly from the faXis ofthe body portion as illustrated in Fig.` 4, sothat the continuous supporting column consisting of these superposed webs, shall obscure as little as possible of the radiationirom the incandescentv interior surface The neck or webis proportioned so that when the ends of the segments are stacked together, as illustrated in Fig, 1, generally in the manner of a log cabin, or otherwise arranged in vertical rows to form amulti-sided cylinder, they will form a solid support for one another and at the same time separate the'segments so that lll) there Iwill be a narrow slotleft therebetween.

The web is preferably disposed intermediate the top and bottom of the segment, and the top of the head 27, the top of the shoulder Q4. and the top of the ridges 31 are preferably' all in the same plane, to facilitate the manufacture of thesesegments without twisting or warping. They distance between the shoulder 24 and the head. 27 isslightly greater .than thewidth of the neck itselfso that when the succeeding ysegments yare placed upon the underlying segments theyl can all move to a sufficient degree to allow for contraction and shoulders and heads zoidal or triangular 1n'crosssection as villusiA excess air.

vao

l serve the purpose scribed above` and also trated in Fig. 7 and are so arranged that the *products` of combustion entirely ing the element of surface catalysiswhen the outer face 28' Vis of greater dimensions 'orj height than the inner face 29, while the lowerl face 30 is inclined downwar ly and outwardly as illustrated.` The top and sides of the body portion are preferably' providedv withw grooves or ridges 31, on the topeiitendv` hose ing generally longitudinally of v the*l body,: while those on sides extend in afgen'erallyi vertical direction. The 'object'of these grooves is to increase ind thereby increase the amount of Vsurface catalysis and thereby secure the complete combustion of the last molecules'of the com'- bustible gases, or in other words, to obtain free "of carbon monoxide with the minimum amount'of In' addition to providing this extended surface, these grooves and'ridges also create a certain amount of turbulence in the gases flowing thereover," thereby assisting' in Y bringing the molecules of combustible gasesA in contact with the molecules' of oxygen wit out having 'a yn iaterial surplus of these mole-f` cales of oxygen. They also add to the amount of radiatingsurface. i y u The lower face 30 of the body ofthe segments, which forms the upper portion 'of the'l slots 'between adjacent segments when-in assembled positionfor the issuanceof the' gases, is covered with'a series of sharp conical or iyramidal projections 32. These projections of extending this surface, turbulencein the gases as dey y due to the fintimate contact with the gases, of reaching a radiant 1' `temperature sooner lthan the `principle mass of refractories and thereby .sooner introducof creating a first put 1n operation. These proburner 1s jections also serve to' increasethc amount of` "adiant heat emanating from'eachl of the slots and thereby adding materially to the maximum transfer of heat by radiation. y lnterme'diate the ends `an ileXtending downwarilly from the lowerfface 30 of the segment, isa leg or member 3?), the lower face ofwhich is coterminus with the lower face off the shoulders 25. When the segments are in assembled 1 the lower faces of the's'houlder 25 position', and member are slightly spaced'. from *the "op of the subi acent segment as illustrated in' v Fig'.7,'thus, asV long asthe segment is intactv the weight thereof is supported by the neck.V or web portion 26 which rests upon-the web of the sub-adj acent segment. However, should the' segment for any reason 'breakI or aimmediately contact .continuous su i the depressions the surface area.v of the segments i tiers of. the

' ance withthe -type of furnace 0r tiers or. rows of ofthe bottom or lower segments. `face 30 tends to restrict too free movement of since it is turning the gases Abustion. fByLvirtue of the i or openings combustion chamber. i

l'. ofi escape ,to ,the ,exterior The angle of divergence between the top and rupturesuch broken-part would onlyk drop or sag a. very short distance at the point of rupture when eitherthe vshoulder or with the underlying segnient which would then carry the weight of the brokenend'of .the segment, the drop or i displacement of the segment being so shg it way disturbs what is in leffect a porting column consisting of all the segments at the corner that it in no vall the `ends o Lwhere they overlap.y VThis construction increasesmateriallythe effective lengthof service ofthe stack of refractories and reduces rel lacement very-great y.

After theringl and sectors 16 have been assembled segments 22 are placed in each of '19- as `illustrated in Fig. 1, after `which@ the remaining segments are laced' in position with the ends overlapping as illustratediin'Fig. 3. Successive rows or segments yare placed in position built up to the ,whichv may vary in accordboiler .with whichfthe/.burnerr is -to be used. Vhen the combustionfchamber or cylinder is built up in thevmanner just-described a series of long narrow slots are formedbetween the segments and the sectors and betweenv therespectivc segments. These slots or openings areffpreferably ofismaller height at the outside than'a-t the insidethis being obtained-by until'the cylinder has been desired height',

y face 30 of each of the AThis,downward-slope of the lower the thrrt the slots and at the samer-time,

downwar wh as such gases tends to rise, it creates an additional turbulence in the gases to secure an ingases 'timate' mixture between the particles of the necessary for their comv similarity of construction of the respective segments the slots betweenv the respective segments vare substantially uniform throughout the This uniformity lof the outlet openings, for the escapeof the. gases, i contributes toa uniform distribution of the gases from the-.combustion thereby `materially increasing the efficiency ofthe-burner to a very high degree, since vthe'segments are brought to a condition of equaliincandescence. at substantially the. sameV time, thus attaining .a greater surface asesand` the oxygen chamber for the -emanation of radiant heat than would otherwise be2-attained.

Radiant Vh surfaces o.,

Wardly thruthe convex-ging slots to a `greater degreez thanwould otherwise be attained by a `slot of uniform dimension from the interior ofI the combustion chamber.

eat emanation from the interior bottom faces theslot is preferably great leg would f ,thecombustion chamber pass out-v the downward slope or inclination invention, the

above and below, so that vin surfaces are obscured vthose. slots.

lsegments the top is p enough so vthat these surfaces .projected across the projected surfaces of the vadjacent slots effect. none rof the interior vertical -froinradiating hea-t directlv tothe boiler or furnace walls through the slots.

The top of thecom'bustion,chamber is closed by a cover .34 preferably -madei-n two pieces to facilitateits insertion thru `the openings in the boileror furnace'. j/lVhen the segments. are laid u or ,assembledl 'ina fashion similar to that o half as many'open sections or spaces at the top as there are segmentsinth-e lcylinder or combustion chamber. Inother words, with a perfectlyiat cover there would bea number of extra` wide. slots which' would `yallowanexcessive amount of suchl .gases .to escape .thru To overcome this or to 4reduce the slots to approximately the. same vdimensions as that of the slotsbetween *intermediate i rovided= with bars or projections 35 so loca-ted that `they fit into the spaces between the topmost segments and re,- luce those spaces to substantially the same size as thev slots between adjacent segments. These bars 35 also interlock Withthe segmentsl and prevent displacement of :the cover. If desired, thetop or cover may be made. circular and i of slightly greater diameter than the stack or combustion chamber so as to slightly overhang the same. This `over-- hanging or projecting portion -o the cover -serves to battle the escaping. gases 'causing -them to scour or scrub the sides of the lrepot in which the combustion ehamberis located. .-This baiilingaction also tends to retain the directly tothe firepot Another possible form ofthe invention is illustrated in Figure 8, wherein lrods 57of refractory 'material' are placedtoget-her to form what may be termed a log/cabin type of combustion chamber. In this form .of the general shape 0f the slots are such thatl the wider portions thereof are dii rected inwardly and that they converge outthey illustration wardlv to-form slots 58 between adjacent rods 57'. The ends ofthe rods are shaped as at 59, to it the ends ofadjacent rods so that', when are assembled, they interlock with each other to form a rigid unit.l While the rods are shown as substantially circular in crosssection, they-maybe triangular, rhombic, or any other form. f It is to be understoodthat I (lo-:not wish to be limited by the exact embodiments of thel device shown, Awhich are merely by way of and not limitation, as various and other forms of theinvention vwill of course be apparent to those skilled in the art without departure from the spirit of the in'vention or the' scope of the kappended claims.

Part of the subject-matter herein claimed is 21, 1927 and which flatter alog cabin there will Y'always :be y

l.reception H.of segments, *a

, the form of a terial located in said uber with long narrow noni my said prior applicatif lo., 4293.537. tiled"Noreni-berl, ltljthanrd z "to this subectfinatter `the present applicatie is a eontii-niat'ion in gj-nnt of said applicatie No. 493,537.. Itfis not my intention to elan in .the present :a p plication vary subject-matte claimed in .said application No. 493.537 or -ii .my prior vapplication. No.20799, filed Jul; application has be come Patent No. 1,898,795), Feb. 21, 1933.

continued "t l.` A- combustion chamber comprising a base Asect1on,.a vplurality of separate ce1-:unie segments superimposed on vsaid-base and arranged in vertical rows each of whichrows forms one Y side yofsaid chamber, sa id segments having spacing ln ie'aills forming intervening slotsrbetween adjacent'.elements of each row, anda-cover for the chamber'formed thereby.

'2. A combustion chamber comprising' a .ibase see-tion, a rpluralityofsegments of ce' ramic 'material superimposed yon said base with the vends thereof yin interlocking relation vto vform the vertical ber, and arranged `to form long narrow slots between adjacent superimposed segments and a .cover superimposed onsai d segments. t

3. lA .combustion chamber .comprising a .base section havingits top arranged for the plurality of segments spaced around the top of vsaid base and coaeting therewith and additional.segments builtfup on said first-named'segments generally like alog cabin with the ends overlappingandwfvith .spaces between the vertically superimposed segments :and forming .a conn buston chamber approxinlately polygonal in planv View, said segmentsb einglaid up in stack and a .cover for 'the top of said stack. 4, A combustion chamber y'comprising a base section `provided with spaced depressed Aportions on Yits top, .segments vof ceramic niadepressed portion and a pluralityof other segments laid up in successive layers tov form. a stack, vthe ends of one-layer interlocking with the ends of the adjacent layer lto form a multisid'ed chamslots between adjacent segments and a cover .superimposedon the last `row layer of, segments.

5. f combustion chamber' comprising a pluralityof interlocking `sectors forming a base, a. plurality of segments of ceramic material spaced around the top` of said sectors .andyadditional segments, the ends of which interlock withy :the ends of adjacent segments laid up in tiers to form a superimposedon the last row Ofsegments.

6. A -combustionvchamber comprising an annular ring of bowl shaped formation on lits interior, va plurality of sectors sin'ierimposed on and interlocking with said ring` and with each other, each. ot said sectors lhaving a depressed portion, a segment of ceramic sides of said cham`r stack and a cover portions and other segments overlapping an coacting with the 'adjacent ends-o the first named s'egments, and arranged' in staggered layers oneabove the other to form a chamber..`

7 A combustionchamber comprisingaii Aon each of saidsec'tors,VV other radiant ele-` ments overlapping andfrestingon' the first named segments. and forming a stack,V there being openings superimposed onsaidstackr basefring having -a bowlsha'pe'd .interior p or.-

tion; threesectors superimposed on said other7 1 sector and spaced therefrom opening therebetween, Otherradiantlelements a radiant elementdisposedfon .each

disposed-between adjacentendsof'the first; lnamed elements and' restingithereon and intherewith and-successive rows l of;-

terloekin radiant e einents 'superimposedon said subjacentA rangement `being such 'that elongated `openings are ormed'betweeneach tlieinterior ofsaid'chamberz` l SQA combustion chamberl coin rising` a base section`V and va plurality. ments superimposed thereonliir 'layers V-an arranged in staggered relationfwth interven-f. elei ing slots' between adjacent superimposed mentsrisai elements overlapping-:at the end" portions thereof which overlappingportionsI form a column off contiguous r endr` 1 members coverorA from the bottom tothe .top anda the top of saidchamber; 3 A combustion chamber t ments arranged in layerswithfv the k'adj acent ends ot the segments overlappingv and interthat there is an interveningfslot betweenadjacent superimposed segments. for the lescape* of the gases of combustion romthe interior j ofsaid chamber. .f 11.`A f 4vcombustion chamber e stack of radiant elements arrariV4 gered layers', rthe contiguous, en

i each orin a narrow jacent superimposed'segments.5.-fy f 12.V A` combustion chamber' comprising a stackbuilt' up of elongatedr .segments arranged in layers andeach i vided with a neck- `at eachendtliere'of,.said segments'being built up tofo'r vft e vertical walls of said chamber, and each of which necks overlaps and interloclrs with the necks of said depressed v ifc'lerlt t Vcent .superimposed segments, isaidrstack, 1 tensions which lie between 'most layer "oi- .segments .to

l.segment.f 13. A combustion .chambe `base section having s tions in the top' thereo 'ing therewith andl Vuousportion; of the base section',`

for the'escape of the products'oi'combustion` vfrom the interior ofsaidfstaekzjandiamover y L y locking` ltherewith, i j l combustio chamberl comprisinga; placed between the endsoi.thesecoridnamed? ij acrwithgeionged ringv and interlocking:tlierewithfand with eachv tol .provide "an tending .the last between each portionl lements and ormingsastack,-the arbase portion and agplul'alty lof longated'l'ele-j jp element'iorlthe;

escape of thefproducts oi combustionfromV staggeredfrelation vment comprisingabodyjpoition an of .ra iant ele-` Imr-row 'slot I j mentsfhe bottom portion J 'f'eachisegment ldeclining .jmiimmmjjy` y,md l.

. `become incandesce t `prising a' stack formed of a series of superimposedsegwjl.

othervv and arranged suchl oiii'prisin g ,a1 ged in l stag-j ds 'of the seg.- l other to thus j slotlike passage-.:betwee`n ad;`

of lwhichsegments "is Jpro-v f of conti saidcoverbcing provide. slots: :be-

tween4 .each .said extension and the` subjace ends ofthe .irstfnarnedfsegment i A .,sucsessive" segments and forming asy slit like openingsbetweenadjaeent'siiperim# ofl the gases off' combustion from the interiorof the;charilbelf` ed Q'YiffheX f :posed segmentsk fortheescape and a top for such stack provid portions @maris-mgl a ous segments, the neck being of sui- .ickness to forme Slot between adje: .and WCYQT rovided .with ei? f t e endsof .theitopU-f .10

vided with ends ,finterlockingv with the'y'cnoxfitig,y f' th? .radiant f gmnsf o itting betweenfthejends of mentfozsubstantially the samedimensi'ons as `f Y' l' the slot between adjacent layers-"of segments..1l

14. A combustion chamber ycomprising Maj ments ksuperimposed thei` en@ fer .,coopertionawith- 'and 'n and arranged m2 kto forma .stack,`"..ea`ch seg-1. Y

d hat n l? .betweenA adjacent layersjoijfseg aow-maxdome? i provided with a sleriesof,protuberancesjwhich' i from the he gases. passing `thru 'the said l stack exte ,ndingA beyond: the yperiphery said stack. i"

gated strip .oi-fradiant mater trapezoidal` in. .cross seetion duced neck .portions liat each en 516, ,Ai-radiant eleme'r'ltv andsides of vwhich are provided withfgrooves hfch. .iS-Pf?? i and ridges and theunder side of' `y o vided ,with'knob Ilike projections and having tedrinember .of ceramic'materal, theftop,"

l substantiall'yA` nd having reiL A there-Of'. 'if v` i .y 00. m Prisme. ai. dori-T angularlydispose'd,ne Jl; portions ateah thereof.,

gated body portion providedwithfridges and grooves on `the top and sides thereof and ing knrobjlikeproj eetions orti-tileI underside, said body providedlwithshoulders projecting from said shoulders.

18. A radiant element for use in a combusradia'nt element comprising an el'ofn-y btb@@de thereofL and angularly disposed yneck vpulirtionsy hay;

lao

'bod tops of which are coterminus with the top of the body portion and the bottoms of which tion chamber comprising an elongated body portion substantially trapezoidal in cross section with the lower side thereofy angularly disposed with reference to thel upper side, said body* portion provided with shoulders angularly disposed with reference to the axis of' the body and neck portions Aprojecting from said shoulders and substantially at right angles thereto.

19. A radiant element for use in a combustion chamber comprising an elongated body portion substantially tra ezoidal in cross section and with the lower ace thereof angularly disposed with reference to the top, said y having shoulders atthe ends thereof, the

projects slightly beyond the lower edge of the body portion, neck portions projecting from said shoulders and arranged atan angle to the body portion, and a head at the'jdistal end of each neck portion.

20. A radiant element for use'in a. combustion chamber, comprising an elongated body portion substantially triangular in cross section and terminating in shoulders at the ends thereof, the lower edges of which project slightly beyond the lower edge of the body, a leg intermediate said shoulders, the rlower edge of which is coterminus with the bottoms of said shoulders, neck portions projecting from each shoulder and arranged at an angle to the axis of the body and a head at the distal ends thereof.

21. A gas burner comprising, in combination with a heater having a lirebox and an ashpit of a. gas burner comprising an elongated box structure extending through said opening and provided with a burner arranged on its upper side substantially at the center of the bottom' of the irebox'and containing means for supplying gas and airto Said burner and in combination with a burner structure of refractory material supported wholly by said box structure over said burner and spaced a substantial distance from the inside of the rebox and constructed and arranged to be heated to incandescence by said burner and to supply heat to the `wall of the flrebox by radiation in a manner simulating the heating thereof by incandescent coal, said burner structure'having a hollow body portion built up generally like a log cabin of separate elements the end of separates two of the other elements to provide an elongated slitlike aperture',` between them, together with a cover over the top of and supported by said body portion.

22. A gas burner comprising, in combination with a heater having a irebox and an ashpit with a side opening, of a gas burner comprising a box structure arranged in said each of whichy ashpit and provided with a burner-arranged to supplyhea't to the wall of thelirebox by radiation in a manner simulating the heating thereof by incandescent coal, said burner structure having a hollow body portion built 11p generally like a log cabin of separate elements the end of each of which separates two of the other elements to provide an elongated slitlike aperture between them, together with a cover over the top of and supported by said body portion. y v

23. A gas-burner comprisin in combination with a heater having a irebox and an ashpit with a side opening, of a gas burner comprising a box structure ashpit and vprovided with a burner .arranged on its upper side substantially at the center` ofthe bottom of the irebox and having means for supplying gas and airto said burner from outside the heater and in combination with a burner structure of refractorymaterial supported wholly by the inner end of said box structure over said burner and spaced a substantial distance from the inside of the lirebox and constructed and arranged to be heated to incandescence by said burner and to supply heat to the wall of the iirebox by radiation in a 'manner simulating the heating thereof by -f incandescent coal, said burner structure having a hollow body portion builtl up generally like a log cabin of separate elements the end of each of which separates two of the other elements to provide an elongated slitlike aperture between them.

24. A hollow burner structure built up of separate refractory elements the end of each of which separates two of the others and which have spacing portions and intervening thinner portions to provide an elongated aperture between them. v

25. A hollow burner structure built up gen-v erallylike a log cabin of separate refractory elements the end of each of which separates two of the others to provide an elongated 'aperture between them, together with a refrac-. tory top supported by said structure.

26. An element of ceramic material for a burner structure having reduced-size fiattened ends each of which is adapted to bev seated between the correspondingly-formed ends of two similar elements.

ASHUR U. WETHERBEE.

arranged in said 

